1. Field of the Disclosure
The present application relates to an organic light emitting display device.
2. Description of the Related Art
Display devices for displaying information are being widely developed. The display devices include liquid crystal display devices, organic light-emitting display devices, electrophoresis display devices, field emission display devices, and plasma display devices.
Among these display devices, organic light-emitting display devices have the features of lower power consumption, wider viewing angle, lighter weight and higher brightness compared to the liquid crystal display devices. As such, the organic light-emitting display device is considered to be next generation display devices.
FIG. 1 is a circuit diagram showing a pixel region of an organic light emitting display device according to the related art.
As shown in FIG. 1, a data line DL and a power supply line PL parallel to each other are formed in a pixel region of the organic light emitting display device according to the related art. Also, a gate line GL is formed in the pixel region in such a manner as to cross the data line DL and the power supply line PL. Moreover, first through third transistors T1 through T3, a capacitor C and an organic light emission element OLED can be formed in the pixel region.
The third transistor T3 is connected to the power supply line PL and controls the power supply voltage Vdd to be supplied to the organic light emission element OLED. The first transistor T1 selectively supplies a data voltage on the data line DL to a gate electrode of the third transistor T3 (i.e., a first node N1) in synchronization with a gate signal, which is applied from the gate line GL. The second transistor T2 selectively supplies a reference voltage Vref to a second node N2 in synchronization with the gate signal on the gate line GL. The third transistor T3 controls a current being applied to the organic light emission element OLED according to a different voltage between the data voltage and the reference voltage Vref, thereby displaying an image.
The recent trend towards larger size of the organic light emitting display device forces the power supply line PL, which transfers the power supply voltage Vdd to the organic light emission element OLED, to be lengthened. As such, the power supply voltage Vdd being applied from one end of the organic light emitting display device must be dropped by the resistance of the power supply line. Due to this, variation of brightness must be generated between one edge of the organic light emitting display device, which inputs the power supply voltage, and the other end. Therefore, picture quality can deteriorate.